Triceratops prorsus
Triceratops prorsus is a species of Triceratops, alongside T. horridus. It lived at the same time and place as its cousin. Classification The T. prorsus was classified as its own species alongside: * T. albertensis (Charles Mortram Sternberg, 1949) * T. alticornis (Othniel Charles Marsh, 1887 [originally Bison]) * T. brevicornus (Hatcher, 1905) (=''T. prorsus'') * T. calicornis (Marsh, 1898) (=''T. horridus'') * T. elatus (Marsh, 1891) (=''T. horridus'') * T. eurycephalus (Erich Maren Schlaikjer, 1935) * T. flabellatus (Marsh, 1889) (=''T. horridus'') * T. galeus (Marsh, 1889) * T. hatcheri (Lull, 1907) * T. ingens (R. S. Lull, 1915) * T. maximus (Barnum Brown, 1933) * T. mortuarius (Edward Drinker CopeCope, 1874) (nomen dubium; originally Polyonax mortuarius) * T. obtusus (Marsh, 1898) (=''T. horridus'') * T. serratus (Marsh, 1890) (=''T. horridus'') * T. sulcatus (Marsh, 1890) * T. sylvestris (Cope, 1872) (nomen dubium; originally Agathaumas sylvestris) All of these species were named, but today only T. horridus and T. prorsus remain as valid species. In 1986, Ostrom and Wellnhofer published a paper in which they proposed that there was only one species, Triceratops horridus. Part of their rationale was that generally there are only one or two species of any large animal in a region (modern examples being the elephant and the giraffe in modern Africa). To their findings, Lehman added the old Lull-Sternberg lineages combined with maturity and sexual dimorphism, suggesting that the T. horridus-''T. prorsus''-''T. brevicornus'' lineage was composed of females, the T.calicornis-''T.elatus'' lineage was made up of males, and the T. obtusus-''T. hatcheri'' lineage was of pathologic old males. His reasoning was that males had taller, more erect horns and larger skulls, and females had smaller skulls with shorter, forward-facing horns. These findings were contested a few years later by Catherine Forster, who reanalyzed Triceratops material more comprehensively and concluded that the remains fell into two species, T. horridus and T. prorsus, although the distinctive skull of T. ("Nedoceratops") hatcheri differed enough to warrant a separate genus. She found that T. horridus and several other species belonged together, and T. prorsus and T. brevicornus stood alone, and since there were many more specimens in the first group, she suggested that this meant the two groups were two species. It is still possible to interpret the differences as representing a single species with sexual dimorphism. In 2009, John Scannella and Denver Fowler supported the separation of T. prorsus and T. horridus, and noted that the two species are also separated stratigraphically within the Hell Creek Formation, indicating that they did not live together at the same time.Scannella, J.B. and Fowler, D.W. (2009). "Anagenesis in Triceratops: evidence from a newly resolved stratigraphic framework for the Hell Creek Formation." Pp. 148–149 in 9th North American Paleontological Convention Abstracts. Cincinnati Museum Center Scientific Contributions 3. ''Triceratops prorsus'' in The Land Before Time Triceratops prorsus occasionally appear the form of cameos in The Land Before Time series, having first appeared in VII. They make numerous appearances in the series afterwards. Land-before-time7-disneyscreencaps.com-3026.jpg|A'' Triceratops prorsus'' in VII. Land-before-time10-disneyscreencaps com-187.jpg|A Triceratops prorsus in X'', with its children Unknown ceratopsid 1.jpg|The ''Triceratops prorsus running with the Great Valley citizens in the top right Spotted threehorn.png|The spotted threehorn next to Topps Unknown ceratopsid 3.jpg|The threehorn accidentally uses Tria's model Unknown ceratopsid 4.jpg Unknown ceratopsid 5.jpg Unknown ceratopsid 6.jpg|''Triceratops prorsus'' and Triceratops horridus Unknown ceratopsid 7.jpg|A Triceratops prorsus can be seen in the background Unknown Sauropods.png|Two Triceratops prorsus in The Hermit of Black Rock References Category:Threehorns Category:Fourfooters Category:Dinosaurs Category:Cretaceous Category:Leaf Eaters Category:Land Before Time species Category:TV series Introductions Category:Ceratopsians Category:Chasmosaurinae